An index for assessing heat stress in terms of physiological strain

The objective of this investigation was to develop an index capable of assessing the magnitude of heat stress imposed on young heat acclimatized men exposed to a wide range of combinations of hot environmental conditions, work, and clothing. In order to achieve this objective, two different heat stress indices were developed and evaluated. On the basis of test results, the superior of the two indices has been recommended. The two indices were derived from two separate biophysical models. For young heat acclimatized men subjected to variable work, clothing, and hot environmental conditions, one of these biophysical models predicts the heart rate response, while the other model predicts the rectal temperature response. The predicted physiological responses obtained from these models were then used separately as indicators of the severity of a hot environment.